In general, catheters are used in medical procedures in which tubular structures, lumens, pleural cavities or spaces of the body, such as airways, vessels, organs and joints, are diagnostically examined and/or therapeutically treated. Catheters, which can be introduced into the body through a natural orifice or through an incision, can deliver imaging devices, surgical instruments, implants, fluids, drugs, pharmacologic materials, biologic materials, biologic agents and therapeutics to treat or remedy various pathologies found therein. Catheters also guide and deliver other components, such as guide wires, scaffolds and tools, to the intended site within the body.
Catheters are commonly used with imaging devices to provide direct visualization of bodily cavities for diagnostic and therapeutic purposes. Such imaging catheter systems represent a significant advance in various fields of surgery permitting the performance of the majority of medical procedures through a number of small incisions reducing postoperative pain and enhancing the postoperative recovery. The imaging catheter systems allow a surgeon to perform the procedure through small holes using long instruments and observing the internal anatomy with a visualization device together with the means for illumination, such as incoherent fiber bundle or LED(s).
Flexible, semi-rigid and rigid endoscopes are also widely used in medicine to provide direct visualization for diagnostic and therapeutic purposes. Flexible, semi-rigid and rigid endoscopes are available in many sizes and configurations intended for use in different parts of the body and for a variety of diagnostic and therapeutic procedures. The visualization device (i.e., a fiber optic image bundle or a sensor at the distal tip of the device), together with the means for illumination, are an integral part of the endoscope. Endoscopes may also provide working channels to guide and deliver other instruments to the desired site.
In all medical procedures that employ medical imaging devices, such as imaging catheters or endoscopes, the objective lens and the illumination device of the imaging device often becomes soiled or obscured during operative procedures by fog, blood, other body fluids or tissue particles. Due to the small size of the objective lenses, any droplet of liquid or moisture, or piece of tissue results in a dramatic compromise of the field of view, requiring the surgeon to pause the procedure in order to clean the lenses.
A common prior art approach for dealing with such obscuring of the distal lens has been to remove the imaging device from the patient and to manually clean it. For example, there are commercial cleaning kits available, including a sponge or fabric pad and a bottle of cleaning solution. The surgeon has to remove the imaging device from the patient, soak the sponge with the cleaning solution, clean the imaging device by wiping the distal lens against the sponge, and then reinsert the device into the patient. While this approach works to temporarily clean the imaging device lens, it has apparent disadvantages. The need to withdraw the imaging device from the patient, clean it, reinsert it, and relocate the target is highly inefficient and inconvenient. Furthermore, the entry port into the patient often collects blood or other debris, and once the imaging device is reinserted into the patient after the manual cleaning, the distal lens of the imaging device immediately becomes dirty again. Therefore, just keeping the lens of an imaging device clean enough to enable a particular medical procedure is often quite inconvenient and significantly extends the operative time of the procedure.
There have been a number of attempts to overcome the disadvantages of the above described cleaning systems. For example, it has been proposed to incorporate spray washing systems on a catheter that is used with the imaging device to allow cleaning of a distal lens without removing the imaging device from the patient. Examples of such systems are described in U.S. Pat. No. 5,313,934 to Wiita et al., U.S. Pat. No. 6,409,657 to Kawano, and U.S. Pat. No. 8,001,984 to Sasaki. While these prior art systems are more efficient than the external cleaning systems, they still suffer from a number of drawbacks. Such systems typically require incorporation of at least one additional lumen and associated hardware for the wash system, which further complicates construction of the imaging catheter, making it more expensive and requiring a larger diameter. Additionally, washing of a distal lens by simply spraying it with liquid while the device is in place will not always be effective in cleaning the lens. Furthermore, the requirement of incorporating a washing system in the medical device itself does not permit cleaning of existing medical devices already in use, and requires replacement with models incorporating a wash system, which can be relatively expensive.
Other prior art systems, such as those described in US 2009/0105543 to Miller et al. and US 2009/0250081 to Gordin et al., utilize standalone cleaning devices that are introduced into the surgical area via a secondary port in the patient's abdomen. While such devices may be more effective in cleaning the lens of an imaging device, they require an additional incision and thus are more invasive. Additionally, because a surgeon is required to manipulate the imaging device and the cleaning device at the same time, such cleaning procedures are more complicated and time consuming. Furthermore, such cleaning systems are difficult to use in small bodily cavities/spaces.
What is desired, therefore, is a system and method for cleaning medical imaging devices that is more effective than known systems that employ fluid to clean the lenses of the imaging device. What is also desired is a cleaning system that is more cost effective, disposable, and simpler in design. It is further desired to provide a cleaning system that allows a surgeon to clean the imaging device lenses without the need to remove the device from a patient's body and that can be inserted through the same incision as the imaging device. Yet further, it is desired to provide a cleaning system that can be used with existing medical devices already in use.